The Formation of the Third Coalition Against France

The early 19th century witnessed Europe’s continued struggle against Napoleonic France’s expanding influence. By April 1805, Britain and Russia formalized their alliance through treaty, marking the birth of the Third Coalition. This anti-French alliance grew substantially by August when Austria completed its military mobilization and joined the coalition alongside Sweden. Even the Kingdom of Naples joined on the eve of hostilities. The coalition devised an ambitious strategy involving multiple coordinated attacks across different fronts.

Austria’s Archduke Charles would lead 150,000 troops across the Adige River into Napoleon’s newly proclaimed “Kingdom of Italy.” British forces from Malta and Russian troops from Corfu would reinforce Neapolitan forces advancing northward. Meanwhile, combined British, Russian, and Swedish forces would recapture Hanover, while Archduke Ferdinand would march from Vienna along the Rhine with 60,000 Austrians and 90,000 Russians. A third Austrian army of 50,000 in Tyrol stood ready to support either Ferdinand in the north or Charles in the south. The coalition’s total strength reached 400,000 men, significantly outnumbering Napoleon’s available forces of just 200,000.

Napoleon’s Strategic Preparations

While the coalition forces gathered in Vienna, awaiting the arrival of Russian General Kutuzov’s troops still weeks away from crossing the Inn River, Napoleon had already prepared his Grande Armée along the Channel coast. His camps stood ready for immediate deployment with minimal orders required. Recognizing that the Danube would become the campaign’s decisive theater, Napoleon planned to strike before the Russian and Austrian forces could unite.

The French emperor intended not merely to push General Mack’s Austrian forces back across the Inn but to destroy them completely. His strategic vision mirrored suggestions he had made to General Moreau five years earlier, with Ulm once again becoming the focal point. Marshal Ney’s familiarity with the Ulm terrain from earlier battles proved invaluable as the campaign unfolded.

The Grande Armée in Motion

On August 27, 1805, Ney received orders to march toward the Rhine. His corps, consisting of three infantry divisions and cavalry support totaling 21,250 men with 36 artillery pieces of varying calibers, began movement on August 31. The logistical challenges were significant, with four different artillery types complicating ammunition supply. The march to the Rhine at Seltz and Lauterbourg covered 262.5 French leagues (approximately 650 miles) in 26 days, passing through Arras, Reims, Chalons, Vitry, St. Dizier, Nancy, and Saverne.

By late August, six French columns stretched from the Rhine to Strasbourg. Napoleon’s masterstroke involved sending Marshal Murat’s cavalry through the Black Forest to deceive Mack into believing the main French attack would come from the west. In reality, the Grande Armée would swing north of the forest and cut off Austrian supply and retreat routes near Ulm.

The Crossing of the Rhine and Initial Engagements

Ney’s corps faced its first challenge at Seltz, where the promised bridge had not been built. Selecting an alternative crossing point near Lauterbourg with favorable island formations, Ney personally supervised the construction of a pontoon bridge. On September 27, the Sixth Corps crossed the Rhine, with soldiers decorating their hats and coats with oak branches “as laurels,” according to one observer. By September 30, Ney’s forces concentrated at Stuttgart, awaiting other corps to complete their deployments.

The French army’s disposition was as follows:
– First Corps (Bernadotte) at Frankfurt-am-Main
– Second Corps (Marmont) at Mainz
– Third Corps (Davout) opposite Mannheim
– Fourth Corps (Soult) at Speyer
– Fifth Corps (Lannes) and Imperial Guard at Strasbourg with Murat’s cavalry reserve

On October 3, the entire army pivoted southward toward the Danube downstream from Ulm. Ney’s corps formed the southernmost element of this turning movement, bringing them closest to Austrian forces. Remarkably, Mack remained unaware of the French maneuver, still expecting an attack through the Black Forest from the west.

The Battle of Elchingen: Ney’s Finest Hour

The campaign’s turning point came at Elchingen on October 14. After Austrian forces under General Mack had attempted to break out northward, Napoleon ordered Ney to attack the Austrian positions at Elchingen to drive them back into Ulm. The battle showcased Ney’s tactical brilliance and personal courage.

Facing Austrian positions on heights overlooking the Danube, with the village of Elchingen and its fortified abbey on their left, Ney’s troops rebuilt damaged bridges under artillery fire. Leading from the front in full dress uniform with his Legion of Honor medal prominently displayed, Ney personally led both infantry assaults and cavalry charges across precarious bridges. Within hours, French forces secured the heights, capturing 4,000 prisoners, hundreds of horses, and several artillery pieces.

Napoleon recognized Elchingen as the decisive action of the Ulm campaign, later granting Ney the title “Duke of Elchingen” in honor of this victory—the first major triumph of the newly established French Empire.

The Surrender of Ulm and Its Aftermath

Following Elchingen, French forces closed the noose around Ulm. By October 15, Ney’s occupation of Michelsberg heights completed the encirclement. After several days of negotiations amid terrible weather and supply shortages on both sides, General Mack surrendered Ulm on October 20. The capitulation yielded staggering results: 25,000 Austrian infantry and 2,000 cavalry laid down their arms, adding to total campaign captures of 60,000 prisoners (including 18 generals), 80 colors, 200 cannon, and 5,000 horses.

While French combat losses were light, the harsh conditions of rapid marches, inadequate supplies, and exposure to cold and rain filled hospitals with sick soldiers. As one officer noted, the campaign’s official histories would record the glory while omitting the suffering behind the victories.

The Campaign’s Final Phase: Operations in Tyrol

With Ulm secured, Napoleon turned east toward Vienna and the approaching Russian forces. Ney’s Sixth Corps received the secondary mission of securing Tyrol, where Archduke John commanded 20,000 regulars and tough mountain militia. Ney innovated by organizing special companies within each battalion—selecting the tallest men for grenadier companies and the most agile for new “voltigeur” (literally “vaulter”) companies to handle mountain warfare.

These specialized troops proved decisive in capturing the key fortresses of Scharnitz and Leutasch on November 4-5 through daring climbs up supposedly impassable slopes. Ney occupied Innsbruck on November 5, capturing significant military stores including 16,000 muskets. Subsequent actions at Staufach and Gries passes secured the Brenner Pass, though a detachment suffered reverses at Botzen on November 25 against Prince Rohan’s forces—the campaign’s final significant engagement.

Strategic Consequences and Lasting Legacy

The Ulm campaign demonstrated Napoleon’s operational artistry at its peak. Through rapid marching and strategic deception, he destroyed a major enemy army before the main coalition forces could unite. This victory set the stage for the even more famous triumph at Austerlitz on December 2, 1805—the first anniversary of Napoleon’s imperial coronation.

Though Ney missed Austerlitz, his contributions at Elchingen and in Tyrol earned imperial favor. The campaign established several enduring military precedents: the value of rapid strategic movement, the importance of deceiving enemy expectations, and the effectiveness of specialized light infantry in difficult terrain. Napoleon’s Grande Armée had proven itself superior to the slower-moving coalition forces, setting a pattern that would dominate European warfare for nearly a decade.

The Peace of Pressburg on December 25, 1805, marked the coalition’s collapse, with Austria surrendering Venice to French control. For Napoleon, the Ulm-Austerlitz campaign represented perhaps his most perfect demonstration of how to win a war through maneuver before the decisive battle was even fought.